Dental impression-tray.



noresms'so'. Patented May 22, I900.

A. BLOCK.

DENTAL IMPRESSION TRAY.

(Appligation filed Oct. 16, 1899.)

(No Model-I Urirrsn dramas LOUIS A. BLOCK, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO ROSS O.

- GRAHAM, OF SAME PLACE.

DENTAL litdFFlESSiGN-TRAY.

SPECIFICATION forming part of Letters Patent No. 856,350, dated May 22, 1900.

Application filed Minter 16. 1 89 to The invention relates to that class of dental-impression-trays which are used in the formation of molds or moutlrimpressions of plastic material, such as piaster-cf-paris; and

its object is to provide a cheap, convenient,-

and sanitary tray.

The invention consists in making the tray of a material that is readily soluble in water, a suitable bonding agent being used, as also a fibrous material for reducing its frangibility, all as fully hereinafter described.

In the accompanyingdrawings, Figure 1 represents a plan view of an upper tray. Fig. 2 is a longitudinal section of the same, and Fig. 3 is a front elevation of the same.

I have deemed it necessary to show only one'form of tray, for the reason that the invention resides not in the particular shape of the article, but in the manufacture of a material having a distinctive characteristic.

The lower tray will of course be formed with the usual central recess for the accommodation of the tongue of the patient.

The tray consists of a body portion A, having a U-shaped depression adapted to re ceive a mass of plastic material, within which an impression of the upper jaw of the patient may be formed. The central portion of the tray shown in the drawings is provided with a strengthening-web a, and to the rearward end of the tray is secured a stem 13, preferably of the same material as the body. The article is made of any plastic granular material intermixed with a fibrous material, a suitable bonding agent, such as glue, being used to cause them to cohere.

In practice I have made the tray of a mixture of plastic and fibrous material, such as a chalk, pipe-clay being employed, and Manila fiber, bonded with any suitable cement, such as glue.

ticular material,as any granular material may he used as a base which will readily soften I do not limit myself to any par- 9. Serial No, 733.706. (No modell) when moistened with water, and any fibrous material may be employed which will reduce the frangibility of the tray when dryo Dental trays have heretofore usually been made of metal. When so made, they are heavy and cumbersome, and it is very difiicult to keep them clean. vantage in their is that they are per nasively in the mouths of a large number of patients, and hence-are unsanitary. Furthermore, not infrequentlythe material does not firmly adhere to the surface of the tray, so that in attempting to withdraw it from the mouth it may leave the mold and adhere to the jaw, to the great inconvenience of both the operator and the patient and sometimes resulting Again, the mold frequently adheres too tenacicusly to the metal tray, and in attempting i0 1 Qsenitt re it shwkemnssefii; tating the making of a new mold, consuming the time of the operator and greatly increas ing the discomfort of the patient.

In use the inner surface of the tray forming the subject of this application softens as with it sufiiciently so that asthe plaster sets it adheres firmly to the tray, enabling the op from the patients month. As soon as the mold the tray quickly softens, so that it may be readily peeled from the plaster. the tray is thus necessarily destroyed in the using.

The cost of manufacture of such trays is so slight that they may be economically used notwithstanding the fact that they perish in the using, and it is obvions that from a sanitary point of View they possess great superi- 'ority. over the trays now in use. I claim as my invention* As an article of manufacture,'&. dental impression-tray formed of a mixture of absorbent granular material and fiber and a bonding agent.

LOUIS A. BLOCK.

-Witnesses:

PAUL CARPENTER, LOUIS K. GILLSON.

in the destruction of the moid.

A decided disadcent in their character and are used successoon as the wet plaster 'comes into contact erator to withdraw the trayand mold easily is sufficien-tly set it is immersed in water and r Of course I 

